X-ray device and x-ray sensitive camera for panoramic tomography and 3d shots

ABSTRACT

The invention relates to an x-ray device ( 50 ) comprising an x-ray sensitive camera ( 55 ) for creating tomograms, especially panoramic tomograms. Means for creating 3D shots of a partial volume of the mandibular arch are also provided, said 3D shots being created especially by a second image receiver ( 5 ) for creating a 2D shot and means for taking a plurality of 2D shots from different directions and creating a 3D shot therefrom, preferably according to conebeam technology with the associated reconstruction algorithms. The x-ray-sensitive camera ( 55 ) comprises a first x-ray sensitive image receiver ( 4 ) for creating a tomogram, and a second x-ray sensitive image receiver ( 5 ) for creating plane shots.

TECHNICAL FIELD

The invention relates to an X-ray system including an X-ray sensitivecamera comprising an X-ray sensitive image detector for the creation ofa tomographic image, and to a camera used for this purpose.

Such an X-ray system is used to produce dental panoramic tomographicimages.

DESCRIPTION OF THE RELATED ART

A dental X-ray diagnostic device for producing panoramic tomographicimages of a patient's jaw is disclosed in EP 0 229 971. In addition topanoramic tomographic images (PAN images), images of one or moreuser-defined, selectable jaw sections can be produced in a plurality ofsuperposed layers (multilayer images). Furthermore, a film cassetteholder is mounted on a rotatable unit bearing the X-ray emitter so thatit can be pivoted from an operating position to a non-operatingposition, which makes it possible to produce teleradiographic images(ceph images), as the X-ray emitter can then direct a beam unhinderedpast the film cassette holder.

An X-ray diagnostic device for the production of X-ray images of partsof a patient's body is disclosed in EP 0 632 994 A1, in which there isprovided a line detector camera with an X-ray detector, the width ofwhich corresponds to the width or the length of the body part to beimaged. The line detector camera can be moved together with the X-raysource along the part of the body to be imaged via regulating means. TheX-ray diagnostic device can thus be configured to produce a PAN image aswell as a teleradiographic image (ceph image), and the line detectorcamera for producing the required image can be unplugged and replugged,for which purpose it is equipped with a connector containing connectingmeans for a detachable mechanical and electrical connection with aholder. Furthermore, various possibilities are disclosed for aiming theX-ray fan beam when producing the teleradiographic image using a movableemitter or a primary diaphragm or a combination of the two.

A camera that is capable of being unplugged and replugged is describedin detail in EP 0 634 671 A1, particular attention being paid to thedetachable mounting of the camera on a holder.

A detector system for the production of X-ray images is disclosed in EP0 858 773 A2 and consists of detectors having dimensions similar tothose of the detector of an intraoral sensor. The detector system is soconstructed that transversal slice acquisition images (TSA images) maybe produced and the detector system can be mounted for displacementalong its longitudinal axis inside the line detector camera. Thedetector elements can be displaced along the main axis of the detectorby adjustment means.

The sensors used in EP 0 858 773 A2 to produce a PAN or a ceph imagetypically have an image height of from 135 to 180 mm and an image widthof approx. 6 mm. The sensors used to produce TSA images typically havedimensions of about 30×20 mm. The difference in width results from thefact that, in the case of a PAN image, it is desirable for the layerthickness (depth of focus) of the sharp slice to be at least the same asthe thickness of the object being imaged, whereas, by contrast, thelayer thickness (depth of focus) of the sharp image in the case of a TSAimage is about 1 to 3 mm.

An X-ray system for producing images is disclosed in DE 199 41 668 A1.The explanations of the cone beam technology disclosed therein areincluded herein by reference in their entirety.

However, the production of cone beam images requires, basically, animage detector different from that used for making a tomographic image,which is usually in the form of a CCD sensor operated in TDI mode. Thesame applies to image detectors that produce individual plane imagesthat are subsequently computed to a tomographic image showing therequired depth of focus. CMOS detectors exemplify image detectors ofthis type.

Although prior art technology already provides for the camera used forthe production of a panoramic tomographic image to be unplugged and thenreplugged for the production of a ceph image, an additional X-ray systemis still required to produce a 3D image.

SUMMARY AND OBJECTS OF THE INVENTION

The invention proposes an X-ray system comprising an X-ray sensitivecamera for creating tomographic images in which there are means in thecamera for the production of images of a subvolume of the jawbone.

The camera is preferably equipped with a primary image detector forproducing a panoramic tomographic image and a second image detector forproducing a 2D image whilst further means are provided for theproduction of a plurality of 2D images from different directions and forcomputation of a 3D image therefrom.

With such an X-ray system it is possible to create both panoramictomographic images using, for example, a CCD sensor operated in TDImode, and 3D images of a volume, preferably using cone beam technologyand the associated reconstruction algorithms.

The second image detector is advantageously a flat face sensor.

Advantageously, control means are provided which enable imaging of asubvolume containing a portion of the PAN image.

Advantageously, adjustment and/or control means are provided by means ofwhich the camera and the X-ray emitter can be adjusted such that thecenter of rotation lies within the subvolume to be imaged. To this end,the camera and the X-ray emitter are advantageously mounted on a commonsupport in the manner known in the art in X-ray systems for theproduction of PAN tomographic images.

According to a further development, adjustment means are provided forthe camera and/or the image detector and/or the X-ray emitter and/or theprimary diaphragm and/or combinations thereof, and the second imagedetector can be moved into the radiation path of the X-ray emitter bymeans of said adjustment means.

Advantageously, adjustment means are provided which cooperate with thecamera, which adjustment means can be built into the camera casing orbuilt into connecting means between the camera and the support ormounted on the support itself.

Adjustment means disposed inside the casing are shielded from outsideinfluences. There is relatively more space available when the adjustmentmeans are mounted on the support, and the camera can be made smaller andlighter.

The X-ray system can, in a development, be additionally equipped with adevice for the production of ceph images using an additional imagedetector. When the X-ray emitter is aligned to produce a ceph image, thecamera is disposed in the region of the path of radiation between theX-ray emitter and the image detector of the device for the production ofthe ceph image and in this region the camera is radiolucent.

Alternatively, the path of adjustment can be dimensioned such that whenthe X-ray emitter is aligned for the purpose of creatingteleradiographic images, the camera can be moved outside the path ofradiation between the X-ray emitter and the image detector of the devicefor producing teleradiographic images.

Both methods have the advantage of not requiring manual intervention forswitching the imaging method from close-up tomographic images (PAN/3D)to teleradiographic images (ceph images).

Advantageously the camera can be mounted so that it is eccentricallyadjustable and can, in a first position, place the image detector inposition for creating a PAN tomographic image and, in a second position,place the image detector in position for creating a 3D image. The X-rayfan beam will then impinge on the image detector provided for creatingthe required image.

An additional object of the invention is the provision of an X-raysensitive camera consisting of a first X-ray sensitive image detectorfor the production of a tomographic image. A second X-ray sensitiveimage detector is provided for the production of plane images.

Such a camera is thus suitable for the production of 3D images as wellas for the production of panoramic tomographic images. The presentinvention makes it possible to create panoramic tomographic images and3D images with one and the same camera.

Such a camera is thus suitable for the production of different types ofX-ray images.

In a first development, both image detectors are mounted in a commoncasing with the camera. This has the advantage that one interface issufficient for effecting both mechanical and electrical connections.

The image-detecting active surface of the second image detector can beat least twice as large as the first image detector, in a firstdimension. Furthermore, the second image detector may be not more thanhalf as large as the first image detector, in a second dimension. Theadvantage of this is that, on the one hand, existing elongated linesensors having dimensions suitable for PAN or ceph images and, on theother hand, existing face sensors having the required width for 3Dimages can be used as image detectors. It is not necessary to provide aPAN sensor having a width sufficient for the production of 3D images,which would cost considerably more than the two individual sensorstogether.

The second image detector is advantageously mounted alongside the firstimage detector. The shoulder freedom of the patient to be X-rayed isthus not impaired by the camera.

The second image detector is advantageously mounted on the rear side ofthe first image detector. Such a camera can be built into traditionalX-ray systems for the production of PAN images and thus provide aretrofitting for the production of 3D images, especially if it ispossible, for example, to unplug the camera, turn it around relativelyto the X-ray emitter, and replug it.

The camera is advantageously designed so that the second image detectorcan be retrofitted. In this case it is possible to first equip the X-raysystem with a camera for the production of PAN images and then, whennecessary, install the second image detector in the camera for theproduction of multilayer images.

According to another development, the second image detector is part ofthe first image detector or vice versa. On the one hand, this allows theimage-detecting surface provided by the second image detector to be usedeven if no images typical for this type of detector are being produced,and, on the other hand, it allows part of the first image detector to beused for the production of the image using the second image detector.

According to another development, adjustment means are provided to bringeither the first or the second image detector, as desired, intoalignment with an X-ray emitter for the production of the respectiveX-ray image.

The adjustment means and both image detectors can be built into a commoncasing with the camera or on the camera casing and in the region ofconnecting means for mounting the camera on a support, and the camera inits entirety is then adjustable relatively to said connecting means. Inthe latter case it is also easy to regulate positioning of the cameravisually from outside and confirm that the correct sensor has been movedinto the proper position for creation of the image. Furthermore, thecamera casing can be kept more compact than when the sensor adjustmentmeans are disposed only within the camera casing.

If the camera has a radiolucent region, it is possible to leave thecamera in the X-ray fan beam for the creation of an additional imagewithout any significant negative impact on the image production. Thecamera can therefore remain in place and need not be removed.

According to a development, the radiolucent region is located betweenthe first and second image detectors.

According to another development, the radiolucent region is locatedadjacent to the first and second image detectors.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the invention is illustrated in the drawings,in which:

FIGS. 1 a and 1 b show a camera with two different image detectorslocated adjacent to each other,

FIGS. 2 a and 2 b show a camera with two different sensors that areoriented back to back,

FIGS. 3 a and 3 b show a first and second adjustment mechanism fordisplacing the sensors inside a camera casing and for displacing thecamera casing respectively,

FIG. 4 a shows a diagram of an X-ray system of the invention for theproduction of PAN and TSA images in a first imaging situation (PAN),

FIG. 4 b shows the X-ray system of FIG. 4 a in a second imaging position(TSA),

FIG. 4 c shows an additional X-ray system having a third imagingposition (ceph),

FIG. 4 d shows an additional X-ray system having an adjustable primarydiaphragm for three imaging positions,

FIGS. 4 e and 4 f are diagrams illustrating various imaging situations,and

FIG. 5 is a further diagram illustrating an eccentrically positionedcamera.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

A camera 1 of the invention is illustrated in FIG. 1 a in a perspectiveview. Camera 1 has a casing 2 in which a circuit board 3 is installed. Afirst image detector 4 in the form of a line sensor is provided on board3, which detector is a CCD sensor in this exemplary embodiment and has alength which is many times greater than its width. The image detector 4can be divided into an image detecting area in the form of a CCD sensor4.1 and read-out electronics 4.2.

Such forms of an image detector are well known in the prior art. Inprinciple, image detectors such as CMOS sensors that produce individualimages in the form of a plane image can also be used.

Adjacent to the first image detector 4 there is provided an additionalimage detector 5, which is constructed in the form of a face sensor andfrom which full frames can be read out at high speed. This imagedetector 4 is also mounted on support board 3, of which the spatialdimensions are, for example, 60 mm×60 mm (height×width) or approximately60 mm×80 mm, so that the image detector can also be mounted more or lesstransversely. It has been found that a subvolume of 60 mm×60 mm×60 mm issufficient to adequately record the areas to be imaged. The exactdimensions must be chosen so that the dimensions of the subvolume to beimaged are covered.

Casing 2 is equipped with mechanical and electrical connecting means 6,7 so that camera 1 can be mounted on a standard support structure (notshown).

A cross section through the camera 1 taken along the line 1 b-1 b inFIG. 1 a is illustrated in FIG. 1 b. Board 3 with the first imagedetector 4 and the second image detector 5 is shown in casing 2, and thesecond image detector 5 is installed in a holding device 8 on board 3.

FIG. 2 a shows a camera 21, which likewise has a casing 2 and a board 3,and the first image detector 4 is mounted on the board 3. The secondimage detector 5, represented by dashed lines, is mounted on the rearside of board 3.

In order to preserve electrical contact when the camera 21 is rotated,the electrical contact 7 is duplicated as 7.1 and 7.2. This doublecontact can obviously also be provided on means (not shown) for couplingthe camera to an X-ray system.

When the camera is rotated as in FIG. 5, a connection that can beunplugged is not required. This rotation can be achieved by a motor ormanually.

The cross-sectional illustration of FIG. 2 b clearly shows theback-to-back arrangement of the two image detectors 4, 5, that is, oneither side of support 3. Image detector 5 is installed in the holdingdevice 8.

Since an X-ray system for the production of a PAN image will beconsidered to be the basic device on account of the fact that suchimages are produced more frequently, the camera can be designed so thatthe image detector 5 for the 3D image can be retrofitted. Retrofittingcan be carried out, for example, by opening the casing and plugging inthe image detector 5 in an appropriate place 8 and making any additionalnecessary electrical or mechanical connections.

Prior art X-ray systems for the production of panoramic tomographicimages have fixed connecting means between the X-ray emitter on the onehand and the detector on the other hand so that both components aremoved together as a unit. As a rule, the detector as such is fastenedrigidly to the common support together with the X-ray emitter.

A first and second adjustment mechanism for positioning the imagedetectors are illustrated in FIGS. 3 a and 3 b.

A camera 41 is shown, which is attached to a support structure 40 andhas a casing 42 in which the image detectors 4, 5 are guided by anadjustment mechanism in the form of a carriage 43 on a guide track 44.The image detectors 4, 5 can thus be moved with the carriage 43 and theadjustment mechanism 44 from the position illustrated to the dashed lineposition 4′, 5′, so that instead of the face sensor of the imagedetector 5, the line detector of image detector 4 moves into the X-rayfan beam represented by the line 45.

In FIG. 3 b, the adjustment mechanism is located between a camera 41 andthe support 40. Camera 41 is mounted via its casing 42 on the supportstructure 40 for displacement thereon, as represented by carriage 43attached to the camera and the guide track 44 attached to the support40. This allows the entire camera 41 to be moved from the positionillustrated to the position represented by the dashed line, so that theX-ray beam, again illustrated by line 45, is aligned not with imagedetector 5 but with image detector 4.

Camera 41 is attached by connecting means and the connecting means canalso include adjustment means. This, however, is not illustrated.

Alternatively, an image can be produced with a motor-driven cameraholder, in which the sensor is positioned according to the desired modeof operation. The motor-driven camera holder forms the connectionbetween the connecting means of the camera and the support. Said holdercan be designed so that the camera plus connecting means can be movedalong a guide track or pivoted by means of a pivoting mechanism. Thusthe camera can be moved automatically into the optimal position in thesystem. A direct image series for a PAN image followed by a multilayerimage can be produced in this manner without any additional interventionon the part of the operator.

The main parts of an X-ray system 50 are illustrated in FIG. 4 a,specifically an imaging device with an imaging unit 51 and an X-rayemitter 52, in which the object to be examined in the form of apatient's head is positioned between the X-ray emitter 52 and theimaging unit 51. For the production of a panoramic tomographic image,the X-ray beam 54 emitted from the X-ray emitter 52 is directed to theimage detector 4 constructed in the form of a line detector, so that therequired length for producing a PAN image of the upper and lowerjawbones is provided.

Meanwhile, the image detector 5 in the form of a face sensor is in aneutral position outside the X-ray beam 54.

An imaging situation for producing a 3D image of a specific subregion ofthe jawbone, such as a single tooth, is illustrated in FIG. 4 b. Thecamera disposed on the imaging unit 51 is now aligned so that the imagedetector 5 is exposed to the X-ray beam 54, and the image detector 4 isnow in a neutral position. Accordingly, in the case of a camera having asensor configuration as in FIGS. 2 a and 2 b, either the image detector4 or the image detector 5 will be oriented toward the X-ray emitter. Forthis purpose, the camera can either be unplugged and replugged orautomatically rotated by a motorized adjustment mechanism.

Obvious to the person skilled in the art, but not always illustrated inthe figures, is the use of a primary diaphragm with mechanically rigiddefault orifices or an orifice that can be regulated by moveablebeam-delimiting elements (not shown) for restricting the extent of theX-ray beam, the extent of the X-ray beam being such that itsubstantially matches the image-sensitive area of the image detector 4or 5 or even perfectly fits the image-sensitive surfaces of the imagedetectors 4 and 5 respectively, in accordance with the relevantstandards. Radiation bombardment by X-rays not needed for the productionof the image is thus avoided.

A diagram illustrating the production of a ceph image is shown in FIG. 4c.

A ceph image can be produced in an X-ray system equipped with a PAN unit“A” and a ceph unit “B” by bringing a separate camera 61, equipped withan image detector 62 with a line sensor of appropriate length for theproduction of the ceph image, into the ceph position. The camera 55 forthe production of the PAN image and the 3D image is positioned so thatthe X-ray beam 54 emitted from the emitter 52 is directed past thecasing of said camera 55.

If a separate ceph sensor is not used, the first camera 55 can beunplugged and replugged manually if the image detector for theproduction of the PAN image located therein is also long enough to fitthe dimensions required to produce the ceph image.

An imaging unit 51 in which there is a radiolucent zone 56 between thetwo image detectors 4, 5 is illustrated in FIG. 4 d. The dimensions ofthe zone 56 are such that a fan beam 54 emitted by X-ray emitter 52 canpass substantially unhindered through the camera.

The camera is stationary in this exemplary embodiment and the fan beam54.1-54.3 is aimed at the appropriate image detector 4, 5, 62 by anadjustable primary diaphragm 57. To this end, the geometric dimensionsof the primary diaphragm 57 are adjusted to the size of the image to beproduced. The width required for the production of a PAN image is, say,0.9 mm.

This principle is illustrated in detail in FIG. 4 e. The primarydiaphragm 57 here has two orifices that allow the passage of theappropriate fan beam 54.1, 54.2 for producing the different types ofimage. The other fan beam is obviously blocked during the production ofan image. The cone of radiation 58 produced by the X-ray emitter issufficiently large to provide the desired fan beam 54.1, 54.2 or, whenneeded, the fan beam for a teleradiographic image.

In lieu of splitting the fan beam 58 emitted from the X-ray emitter 52by an variable primary diaphragm, the X-ray emitter 52 can, if desired,be directed, by adjustment mechanisms, toward either one of the imagedetectors 4, 5, as illustrated in FIG. 4 f. Such an adjustment isalready known for combined PAN/ceph devices. The adjustment may beachieved by sliding or, as illustrated, by pivoting. The advantagegained in this case is that the central ray of the X-ray fan beam 58always lies within the fan beam 54.

With the eccentric mounting of the camera 2 illustrated in FIG. 5, a PANimage can be produced in an initial alignment of the camera 2 in whichthe image detector 4 lies within the X-ray fan beam 54.1. With thisalignment of camera 2 it is also possible to produce a ceph image, asthe X-ray fan beam 54.3 is directed past camera 2. A 3D image can beproduced when camera 2 is in the position represented by the dashedlines, which is achieved by rotating it about the center of eccentricity59. In doing so, the image detector 4 is positioned closer to the X-rayfan beam 54.3 for the ceph image than the image detector 5.

The arrangement illustrated has the advantage that a short jib for theceph camera is sufficient for producing the ceph image, because theX-ray fan beam 54.3 stays close to the wall.

The following fundamental principle must be observed: a differentprimary diaphragm will be used for the production of a PAN image, a 3Dimage, and a ceph image respectively and each image will be createdusing only one imaging method. When several X-ray fan beams areillustrated together in the exemplary embodiments, this serves merely toclarify the geometric relationships. The primary diaphragm, however, isconstructed and adjusted such that the desired image detector isactivated by the correct X-ray fan beam for producing the desired image.

1-21. (canceled)
 22. An X-ray system having an X-ray-sensitive camerafor the creation of tomographic images, which camera includes a firstand a second image detector, wherein said first image detector isprovided for the creation of a panoramic tomographic image and saidsecond image detector for the creation of a 2D image, and means areprovided for the creation of 3D images of a subvolume of the mandibulararch, which means create several 2D images from different directions andcompute a 3D image therefrom, and including adjustment means by means ofwhich said camera and/or said image detector and/or said X-ray emitterand/or a primary diaphragm and/or combinations thereof can be adjustedsuch that said second image detector present in said camera can be movedinto the optical path of said X-ray emitter.
 23. An X-ray system asdefined in claim 22, wherein said second image detector is a facesensor.
 24. An X-ray system as defined in claim 22, including controlmeans are provided such that within the 3D image a subvolume comprisinga portion of the panoramic tomographic image can be imaged.
 25. An X-raysystem as defined in claim 22, including means for the creation of 3Dimages using the cone beam technology with associated reconstructionalgorithms.
 26. An X-ray system as defined in claim 22, includingadjustment means and/or control means by means of which said camera andan X-ray emitter can be adjusted such that the center of rotation liesin the subvolume to be imaged.
 27. An X-ray system as defined in claim22, wherein said adjustment means are provided in said casing of saidcamera or in connecting means between said camera and a support or onsaid support itself.
 28. An X-ray system as defined in claim 22,including an installation for the creation of teleradiographic imageswith another image detector and, when said X-ray emitter is aligned forthe creation of a teleradiographic image, said camera is disposed in theregion of the optical path between said X-ray emitter and said imagedetector of said installation for the creation of teleradiographicimages and is radiolucent in said region.
 29. An X-ray system as definedin claim 22, including an installation for the creation ofteleradiographic images with another image detector and the path ofadjustment is such that, when the X-ray emitter is aligned for thecreation of a teleradiographic image, said camera can be moved out ofthe optical path between said X-ray emitter and said image detector ofsaid installation for the creation of teleradiographic images.
 30. AnX-ray system as defined in claim 22, wherein said camera is mounted foreccentric displacement and, in a first position, said image detector ispositioned in the X-ray fan beam for the creation of a panoramictomographic image and, in a second position, said image detector ispositioned in the X-ray fan beam for the creation of a 3D image.
 31. AnX-ray-sensitive camera, comprising a first X-ray-sensitive imagedetector for the creation of a tomographic image, a secondX-ray-sensitive image detector for the creation of plane images andwherein the two image detectors are disposed in a common casing, andsaid second image detector is disposed alongside said first imagedetector and including adjustment means for the purpose of causing, asdesired, said first image detector or said second image detector toassume correct alignment relative to an X-ray emitter for the creationof the respective X-ray image.
 32. A camera as defined in claim 31,wherein said second image detector is disposed on a rear side of saidfirst image detector.
 33. A camera as defined in claim 32, wherein saidadjustment means and the two image detectors are housed in a commoncasing of said camera.
 34. A camera as defined in claim 33, wherein saidadjustment means are provided on said casing of said camera and in theregion of connecting means for the attachment of said camera to asupport and said camera can be variably displaced, as an entity,relatively to said connecting means.
 35. A camera as defined in claim34, wherein said camera has a radiolucent region.
 36. A camera asdefined in claim 35, wherein said radiolucent region is disposed betweenor alongside said first image detector and said second image detector.